This invention relates generally to aircraft and more particularly to aircraft of the vertical takeoff and landing type. The invention may be generally classified with aircraft exemplified by the types shown in the following patents.
______________________________________ #3,073,548 Marsh January 15, 1963 #3,140,841 Marchant et al July 14, 1964 #3,153,906 Marchant October 27, 1964 #3,174,709 Alderson March 23, 1965 #3,209,535 Marchant et al October 5, 1965 #3,258,206 Simonson June 28, 1966 #3,486,716 Haberkorn et al December 30, 1969 #3,863,869 Bachman February 4, 1975 ______________________________________
While more of the listed patents relate to or show vertical takeoff aircraft, many of them are of the winged type and therefore have control problems and structure for solving the same which differ from those of the present invention.
The invention herein is more particularly directed to aircraft which is devoid of wings which provide lift and a boom or tail which provides stabilizing characteristics, the craft herein relying entirely upon fluid streams to effect lift, propulsion, and control.
Vertical takeoff and landing aircraft are difficult to control in a lover mode of flight because of the limited availability of control energy. Some prior systems have utilized engine bleed air which is ducted to puffer jets in the wing tips resulting in a significant penalty to takeoff power. Some forms of wingless vehicles, ie, small platforms, have depended upon vehicle attitude to develop thrust by vectoring the jet for forward flight, however, to reach suitable forward speeds the tilted attitudes become excessive. All systems require a precise control of the thrust forces relative to the center of gravity to maintain stability since control moments of low inertia vehicles are not sufficient to react the unbalance moments generated by normal center of gravity travel.
Vertical takeoff and landing aircraft of the wingless and and tailless type have inherent control instability problems which require automatic stabilization or excessive pilot effort to maintain control of the aircraft during the transition to forward flight. Ordinarily, in forward flight, a rudder, horizontal stabilizer, or tail rotor is required for directional stability.
One of the objects of this invention is to provide an aircraft of the vertical takeoff and landing (VTOL) type and which is also wingless and devoid of a boom or tail, the aircraft having an engine driven fan and structure to provide fluid streams so directed as to elevate the craft, propel it through the air, and control its direction, stability, and attitude.
Another object of the invention is to provide a VTOL aircraft having a body with an air duct with an inlet and a pair of outlets, one at each side of the body and directed downwardly, an engine driven fan being disposed in the air duct adjacent the inlet and operative to cause air to flow into the duct and be discharged from the outlets, the reactions of the streams tending to urge the body upwardly, cascades of vanes being adjustably arranged in the outlets and operative to direct the streams of air discharged from the outlets angularly relative to the vertical axis of the body to impart forward thrust thereto or rearward thrust to counteract forward movement and interrupt the same.
A further object of the invention is to provide the body of the vehicle mentioned in the preceding paragraph with adjustable door means in the air duct in advance of the outlets and serving to shift the effective areas of the outlets fore and aft to vary the relative positions of the streams issuing from the outlets to the vehicle center of gravity whereby the attitude of the craft might be controlled.
A still further object of the invention is to provide such craft with adjustable vanes exterior of the body and at one side of each outlet to partially restrict the airstreams to further exercise control of the body.
An object also is to dispose the inlet of the air duct adjacent the rear of the body and to position a shield or similar member in spaced relation from the rear of the body so that air may flow laterally into the space between the body and shield and be drawn into the inlet of the duct by the fan, this arrangement providing a momentum drag aft of the vehicle center of gravity which introduces an inherent directional stability for both pitch and yaw of the vehicle. Since the drag is proportional to vehicle velocity for a constant fan flow it is an effective stabilizer from very low forward velocities to maximum operating speeds.
Other objects and advantages will be apparent from the following description of one form of the invention which has been shown in detail in the accompanying drawings.